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Biofabrication Of Human Tissue-On-A-Chip Models Using Engineered Biocompatible Electrospun Scaffolds
Get PDFThis study explored the adoption of furfuryl gelatin (F-gelatin) based electrospun scaffolds compared with poly-caprolactone (PCL) as promising biomaterials for tissue engineering applications. Tissue-on-a-chip models, incorporating F-gelatin and PCL electrospun scaffolds, offer promising avenues for healthy and disease-in-vitro tissue models that can be explored to investigate underlying physiological mechanisms involved in disease development. Previous research has demonstrated the cytocompatibility of F-gelatin when used for modifying implant surfaces and tissue repair applications [1]. Our earlier published works have also successfully utilized F-gelatin for in-vitro cardiac tissue engineering [2][3]. We designed F-gelatin and PCL electrospun scaffolds to replicate the native tissue extracellular matrix (NT-ECM) environment. Additionally, we hypothesized that blending the hydrophilic F-gelatin with hydrophobic PCL would result in mechanically robust scaffolds capable of supporting the retention and viability of cells, essential for establishing a successful in-vitro tissue model. Since the electrospinning method offers versatility in controlling fiber alignment and composition, allowing for the generation of scaffolds that closely resemble the NT-ECM, we aim to optimize the electrospinning parameters to yield scaffolds that possess excellent mechanical fidelity, biocompatibility as well as the ability to sustain long-term culture periods. Specifically, we will study the effects of optimizing electrospinning parameters such as rotational speed, deposition distance, and voltage to evaluate their impact on the resultant scaffolds. Two collection speeds, static (0 RPM) and dynamic (\u3e100 RPM), will be compared to assess their effects on scaffold fiber alignment as well as orientation and its correlation with the scaffoldâ??s biological properties. To facilitate these experiments, we have developed an in-house electrospinning system capable of recording the various electrospinning parameters via an Arduino setup, which has led to reliable and reproducible results for tissue engineering applications [4]. Samples will be characterized for mechanical fidelity via SEM (Scanning Electron Microscopy), FTIR-ATR (Fourier-Transform Infrared - Attenuated Total Reflectance), and DMA (Dynamic Mechanical Analysis). Finally, three different applications will be developed using these scaffolds, including their use in 1) seeding and differentiation of neural progenitor cells for studying neurodegenerative diseases, 2) for the development of cardiac cell models to study the onset of diabetes, and 3) adoption in tissue on-a-chip models to be tested under microgravity and other extreme environmental conditions. Overall, this project contributes to developing novel NT-ECM for biocompatible human tissue-on-a-chip models via the biofabrication of electrospun scaffolds
Interview no. 1792
No full textMr Velez grew up in Segundo Barrio during the 1970s, 1980s, and 1990s. He associates those times with gang warfare because of the introduction of guns. He also remembers that in Segundo Barrio, many families lived in tenements. With the number of people living in the tenements, there were a lot of activities in the community, including social gatherings, parties, and family parties. In the absence of technology, most time was spent outside, whether it was hearing local gossip, visiting family and friends, or socializing; that was life in a small community. He lived in a tenement on the corner of Campbell and Father Rahm with the famous Arturo Ramirez mural with Segundo Barrio on the top; the mural was from the La Campaña program organized by Carmen Felix’s beautification project to showcase the community and protect it from El Paso city plans to demolish the tenements in Segundo Barrio for commercial business. Mr. Velez remembers playing outside but also reminisces about numerous activities available at the recreation/community centers. These activities ranged from sports, movies, dances any way to promote socializing and have activities for youth/teens. The recreation centers (Boys Club, Houchen, and Sacred Heart Church) were the most memorable for him. He remembers the Kermes, rides, playing around, festivals, and other city events that had rides and other city events. As Mr. Velez grew older, he couldn’t continue to visit the community centers because of gang involvement, but he remembers that, in his youth, someone was always playing a sport in Armijo field. When thinking of playgrounds, schools, and facilities in general, the one thing that stood out to him was the trees. There were lines of trees, a bunch of beautiful trees. There were trees in the practice fields at different schools; he remembers Willow Trees and many bushes everywhere. He recalled that this area was called El Bosque. Speaking of Segundo Barrio in the present, Mr. Velez feels that the community appeared to have just left from one day to the next, and then developers and property owners started cutting trees to save on irrigation. He recounts summers in the park under the trees for protection from the heat. Just as important as trees are his concept of community and its progression. Elaborating on components of community that are now missing, local stores, local restaurants, and lack of socializing. Mr. Velez also equates walking with socializing, which he believes is fundamental in the community. He concludes by sharing his vision of community, the importance of preserving history, and the responsibility of the community to provide activities and education for its children instead of focusing on the aesthetics of buildings
Perspectivas De Liderazgo En La Frontera: Un Análisis De Las Experiencias De Los Presidentes Y Cónsules De El Paso Y Ciudad Juárez
No full textCiudad Juárez y El Paso son el reflejo de México y Estados Unidos a nivel municipal, sin embargo, esta unión de ciudades a nivel fronterizo abre las puertas a oportunidades únicas al igual que desafíos significativos, los cuales pueden ser el resultado de las relaciones macro de ambos países, pero también de ambas ciudades. Por lo tanto, las ciudades fronterizas son el ejemplo de una amalgama de representación local y binacional, ya que los líderes que se encuentran en estas ciudades; como cónsules generales, y presidentes municipales, reflejan no solo la personificación de la ciudad, sino también el símbolo e imagen de México y Estados Unidos. Cada uno de ellos con distintos trabajos, deberes y asignaciones, los cuales forman un crisol de interdependencia que incorpora tanto a las ciudades como a las naciones. Así bien, cada autoridad tiene su homologo a través de la frontera, lo que conlleva no solo al dialogo transfronterizo, sino también a la cooperación bilateral entre México y Estados Unidos a través de líderes locales. Por ende, cada autoridad representa un punto de vista ajeno, el cual se vincula holísticamente a un entrono compartido que se ve reflejado en la interdependencia que trasciende en las respuestas locales a contextos nacionales e internacionales.
En consecuencia, esta tesis tiene como finalidad explorar en detalle cómo estos líderes han percibido y abordado la interdependencia y dinámica fronteriza durante sus respectivos mandatos. ¿Cómo han interpretado la interacción transfronteriza? ¿Qué oportunidades han identificado en esta región? ¿Qué lecciones pueden extraerse de sus experiencias? Por ende, mediante un enfoque cualitativo, esta investigación analiza las perspectivas de los presidentes municipales y cónsules generales de Ciudad Juárez y El Paso, estudiando sus experiencias y percepciones sobre el dinamismo fronterizo. Por consiguiente, los resultados de este estudio no solo contribuirán a la comprensión de las relaciones entre Ciudad Juárez y El Paso, sino que también se innovará en los estudios fronterizos, al incluir en vez primera historia la oral en las humanas, políticas y diplomáticas experiencias de los presidentes y cónsules de Ciudad Juárez y El Paso
Accessibility and Usability of Medical Devices for Users with Disabilities: Insights from a Bibliometric and Thematic Analysis
No full textElucidating The Effect Of Milled Glass And Graphite Fiber On The Quasi-Static Properties Of Vinyl Ester Resin Composites
No full textComposite materials can be tailored to various applications, making them one of the most conventional materials. Their ability to enhance desired characteristics enables higher strength while maintaining light weight. However, understanding defects and manufacturing limitations is crucial for optimizing their fabrication processes. This paper focuses on the manufacturing processes of open molding with controlled variations to establish an optimal technique aimed at minimizing defects, such as bubble formation where the focus is on mitigating defects and ensuring uniform dispersion of fiber in fiber-reinforced composites. After refining the manufacturing process, composites with varying resin-to-fiber concentration ratios were manufactured using glass and graphite fibers. These samples were subsequently evaluated under quasi-static loading conditions, including bending and tensile tests, to analyze the impact of manufacturing variables on the mechanical properties of the composites. This investigation highlighted bubble formation as a critical manufacturing defect due to the significant impact on the material\u27s properties. In addition, an increase in fiber reinforcement led to a higher viscous mixture, making the manufacturing more prone to bubble formation. It was concluded that the integration of heat improved with the mitigation of bubble formation, and reduced deviations between samples
Fatigue Endurance Of Alsi10mg Post Hip Heat Treatment With High Duration Thermal Aging
No full textAlSi10Mg is one of the cornerstones of additive manufacturing (AM), with its materialproperties and relatively low cost making it extremely popular as an AM metal choice, specifically using Laser Powder Bed Fusion (LPBF). Many publications have focused on this material, studying tensile strength, fatigue, heat treatments, and more. However, an area that requires further study is the effect of aging on the materials fatigue properties, with this study examining an industry standard heat treatment of Hot Isostatic Pressing (HIP). Using studies that have already been completed, AlSi10Mg was fatigue tested at near 100% UTS and 75% yield strength after HIP and aged 0, 10, 100, or 1000 hours. The discovery from testing was that aging reduced the material fatigue strength, with effects seen from as little as 10 hours of aging. This is likely due to the over-aging precipitates of Si forming in the internal microstructure, changing the originally ordered microstructure from the as-built and heat-treated to have increasingly granular Si precipitates with respect to aging. Their removal from the structure likely causes microvoids to form, leading to crack propagation once the material is sufficiently stressed, reducing the fatigue performance
The United States National Security And Policy Implications Of Desertification
No full textContemporary climate security literature reveals that desertification appears to be overlooked as a climate change security threat to the United States (US). This investigation demonstrates that an inequity exists between sea-level-rise- and desertification-based climate security literature. This inequity may reveal that the US may be ignoring desertification at a time when land use in some dryland areas is reaching a critical point where it can no longer support human activity. Due to the interdisciplinary nature (science and security) of this work, a review of the terminology used in the article is provided to establish a baseline understanding of “desertification” and other arid land-based processes, and “securitization” and climate security.
An overview of what domestic and international desertification looks like is presented so that the types of threats that desertification presents can be realized. The domestic scenario discusses the US’ core deserts, reveals the fact that desertification is already affecting the US, and how future desertification in the US may expand. The drying of the Earth (dubbed “dearth”), in terms of surface and ground water, are considered, along with the expectation of increasing dust and wildfires and their effects. Lastly, direct examples of military operations that have already been affected are discussed. Since the risks of desertification are not limited to domestic occurrences, the effects of international desertification that have the potential to impact US national security are also considered. For the international scenario, the US Intelligence Community (IC) identifies 11 countries and two regions where climate change poses a serious threat. Among these countries and regions, desertification is the greater concern in terms of the number of entities that are affected. A review of the types of threats that international desertification creates is presented along with the expected role that the US will play. A policy review is also considered with a quick examination of the government’s most recent actions to combat climate change. Again, this review reveals that desertification is simply not on the climate change agenda as even the preeminent government document, the Fifth National Climate Assessment, does not fully recognize desertification. It appears that the US is ignoring the desertification threat and that this oversight may leave the US vulnerable to climatic effects that it is not currently accounting for
“Don’t Bring Your Feminism Here!”: The African Hair Braiding Salon As A Rhetorically Charged Space For Feminist Activism
No full textThis project extends scholarship on Black beauty and hair care spaces in the US as rhetorically charged for various forms of activism. It specifically explores the nature of work, conversations and feminist ways of being among a group of braiders working together in an African hair braiding salon to legitimize the African hair braiding salon as a site with unique contributions to this body of work. Grounded in Feminist Geo-criticism and Conversational Rhetoric, the study seeks to make contributions that are relevant to the field of Rhetoric and more specifically the sub-field of feminist rhetorics, African and non-Western feminist rhetorics, Transnational feminism and gendered perspectives on immigration. The project seeks to answer calls pushing for more inclusion in our recovery of women\u27s voices and their contributions to rhetorical theory. Ultimately, it seeks to determine how else we could extend African feminist activism into certain demographics offline and to challenge the common perception that feminism is un-African. To which this study found through a series of interviews with braiders in a salon that African women in informal settings construct their own feminist identities and move towards a new feminist ethos where they embrace feminism with no threat to their religious identities as good Christian wives. This is useful for theorizing around the conditions that facilitate the sort of learning and unlearning that goes on in the space, the models of learning that contribute to this process, and the forms of knowledge-mediation that occurs to advance feminist activist work on the continent and in African spaces abroad
Configurable Toolpath Optimization For Extrusion Additive Manufacturing
No full textIn additive manufacturing, a software program called a â??slicerâ?? is used to create toolpath instructions to command a 3D printer. This slicing program imports a CAD geometry, typically as a mesh file such as an STL, â??slicesâ?? it into layers, fits toolpaths to each layer, then exports g-code to be imported to the 3D printer. This approach can be used on many types of 3D printers from filament extrusion, to syringe thermoset deposition, to wire arc welding. While each of these processes use different feed stocks and hardware configurations, the underlying slicing approach remains the same. During the path planning step of the slicing process, the toolpaths are typically optimized to connect the disparate paths together in a way that, ideally, minimizes travel distance for the deposition head. While these optimization strategies are often effective at decreasing total travel distance, they may unintentionally increase print time and decrease mechanical properties.This dissertation takes an in-depth look at what these optimization strategies are and how they work. A new implementation for optimization strategies is created via open-source software to allow more control over the path optimization process. Finally, the optimization strategies are rigorously tested with polymer extrusion to show how different optimization strategies impact print time, total path length, slicing time, heat distribution, geometric accuracy, mechanical performance, and layer to layer bonding
Thermal Inequity Along The US-Mexico Border: An Analysis Of El Paso, Texas
No full textThe Urban Heat Island effect (UHI) combined with rising average global temperatures invariably results in thermal inequality, the unequal distribution of temperature patterns by different socioeconomic and sociodemographic groups, resulting in an array of negative public health impacts. This thesis research focused on the historical factors that contribute to UHI and tree cover in historically underserved neighborhoods in El Paso, Texas. The impact of maps from 1933-1954 created by the Home Ownerâ??s Loan Corporation (HOLC), a federal selective lending program, resulted in decades of disinvestment and inequality especially in redlined areas. Geospatial analyses of environmental and socioeconomic indicators such as tree cover, land classification, temperature, social vulnerability index (SVI), and percent of population below poverty by HOLC category using the 1936 city boundary were conducted to determine the conditions and vulnerabilities of each HOLC area today. Additional qualitative analysis was conducted through structured interviews with the City of El Paso and the National Weather Service (NWS) to determine how each agency identifies and serves vulnerable populations, their respective missions regarding climate and heat, and how they plan to improve operations moving forward. Further, exploration of relationships between historical zoning and lending practices in El Paso and the environmental legacy that continues until today revealed that it magnifies vulnerabilities in underserved communities. The qualitative and quantitative research helped determine that HOLC practices in El Paso have resulted in the unequal distribution of infrastructure and socioeconomic conditions. Results of decades of racially motivated city planning, housing discrimination, and segregation are clear today in the variations of availability of green amenities such as trees and parks throughout historically segregated areas in El Paso. Future larger-scale studies of thermal and environmental inequity in El Paso both spatially and temporally could fill in gaps needed to produce more comprehensive data regarding how the legacy of racially-determined zoning may be increasing community vulnerability to environmental extremes at the neighborhood scale and the metro scale